Check in a simple pure-python based Markdown previewer.

third_party/Python-Markdown/markdown/extensions/__init__.py

+"""
+Extensions
+-----------------------------------------------------------------------------
+"""
+
+from __future__ import unicode_literals
+from ..util import parseBoolValue
+import warnings
+
+
+class Extension(object):
+    """ Base class for extensions to subclass. """
+
+    # Default config -- to be overriden by a subclass
+    # Must be of the following format:
+    #     {
+    #       'key': ['value', 'description']
+    #     }
+    # Note that Extension.setConfig will raise a KeyError
+    # if a default is not set here.
+    config = {}
+
+    def __init__(self, *args, **kwargs):
+        """ Initiate Extension and set up configs. """
+
+        # check for configs arg for backward compat.
+        # (there only ever used to be one so we use arg[0])
+        if len(args):
+            if args[0] is not None:
+                self.setConfigs(args[0])
+            warnings.warn('Extension classes accepting positional args is '
+                          'pending Deprecation. Each setting should be '
+                          'passed into the Class as a keyword. Positional '
+                          'args are deprecated and will raise '
+                          'an error in version 2.7. See the Release Notes for '
+                          'Python-Markdown version 2.6 for more info.',
+                          DeprecationWarning)
+        # check for configs kwarg for backward compat.
+        if 'configs' in kwargs.keys():
+            if kwargs['configs'] is not None:
+                self.setConfigs(kwargs.pop('configs', {}))
+            warnings.warn('Extension classes accepting a dict on the single '
+                          'keyword "config" is pending Deprecation. Each '
+                          'setting should be passed into the Class as a '
+                          'keyword directly. The "config" keyword is '
+                          'deprecated and raise an error in '
+                          'version 2.7. See the Release Notes for '
+                          'Python-Markdown version 2.6 for more info.',
+                          DeprecationWarning)
+        # finally, use kwargs
+        self.setConfigs(kwargs)
+
+    def getConfig(self, key, default=''):
+        """ Return a setting for the given key or an empty string. """
+        if key in self.config:
+            return self.config[key][0]
+        else:
+            return default
+
+    def getConfigs(self):
+        """ Return all configs settings as a dict. """
+        return dict([(key, self.getConfig(key)) for key in self.config.keys()])
+
+    def getConfigInfo(self):
+        """ Return all config descriptions as a list of tuples. """
+        return [(key, self.config[key][1]) for key in self.config.keys()]
+
+    def setConfig(self, key, value):
+        """ Set a config setting for `key` with the given `value`. """
+        if isinstance(self.config[key][0], bool):
+            value = parseBoolValue(value)
+        if self.config[key][0] is None:
+            value = parseBoolValue(value, preserve_none=True)
+        self.config[key][0] = value
+
+    def setConfigs(self, items):
+        """ Set multiple config settings given a dict or list of tuples. """
+        if hasattr(items, 'items'):
+            # it's a dict
+            items = items.items()
+        for key, value in items:
+            self.setConfig(key, value)
+
+    def extendMarkdown(self, md, md_globals):
+        """
+        Add the various proccesors and patterns to the Markdown Instance.
+
+        This method must be overriden by every extension.
+
+        Keyword arguments:
+
+        * md: The Markdown instance.
+
+        * md_globals: Global variables in the markdown module namespace.
+
+        """
+        raise NotImplementedError(
+            'Extension "%s.%s" must define an "extendMarkdown"'
+            'method.' % (self.__class__.__module__, self.__class__.__name__)
+        )